The present invention is in the field of electrical connectors. Specifically, the present invention is related to assisted-release electrical connectors.
Many electrical devices rely upon electrical cables such as power cords to connect the device to a power source, such as a wall-mounted electrical outlet. Additional electrical cables, such as extension cords, are often required to extend the range of the electrical device from an outlet due to limited outlet availability or because the power cord of the electrical device is too short to reach an available outlet.
An electrical cable typically comprises insulated conductors, such as wire, of a desired length. Typically, one end of the electrical cable terminates in a male connector, while the opposite end terminates in the electrical device or a female connector. Connectors are designed to terminate conductors and cables between electrical circuits within a system, between systems, and between systems and external power sources and signal lines.
A male electrical connector is commonly referred to as a xe2x80x9cplug.xe2x80x9d Female electrical connectors are also commonly called xe2x80x9creceptacles,xe2x80x9d xe2x80x9csockets,xe2x80x9d xe2x80x9cjacks,xe2x80x9d or xe2x80x9coutlets.xe2x80x9d Examples of plugs in the art include, but are not limited to a flat blade plug as shown in FIG. 1A (along with an electrical outlet), and a flat blade plug with a grounding terminal as shown in FIG. 1B. A male electrical connector, i.e., plug, typically mates with a female connector of the same size and number of conductors.
As shown in FIG. 2, a male electrical connector 200 may comprise a body 202 made from an electrically insulative material. The body 202 has a mating surface 204 from which conductive projections 206 extend. The mating surface 204 can be pressed substantially against a mating surface 304 of a female connector (shown in FIG. 3) so as to place the two connectors in electrical communication. The body 202 of the male connector typically houses the electrical connection (not shown) between the conductors in an electrical cable 208 and the conductive projections 206.
As shown in FIG. 3, a female electrical connector 300 may comprise a body 302 made from an electrically insulative material. The body 302 has a mating surface 304 in which cavities 306 are formed. The cavities 306 contain conductive receivers 308 adapted to accept the insertion of conductive projections 206 (shown in FIG. 2). The body 302 of the female electrical connector 300 typically encapsulates the connection (not shown) between the conductors within an electrical cable 310 and the conductive receivers 308.
Typically, a plug is held in a receptacle after insertion due to a friction fit between the conductive projections of the male connector and the corresponding conductive receivers of the female connector. The friction fit is due to the insertion force required to overcome the interaction of the conductive projections of the male connector with the conductive receivers of the female connector when coupling the connectors, and is a desirable characteristic in order to achieve and maintain a good electrical connection.
A male connector coupled with a female connector is referred to as a xe2x80x9cconnector assembly.xe2x80x9d A connector assembly can typically be uncoupled by applying sufficient force to pull the male and female connectors apart. However, the amount of force required to uncouple the connectors can often be excessive for a number of reasons, creating difficulty in separating the connectors. Connector assemblies can also be difficult to uncouple if the connector assembly is located in a partially obstructed or difficult-to-reach area such as behind furniture. Another factor that can make connector assemblies more difficult to uncouple is the addition of more conductors, such as a grounding terminal, which increases the friction fit between the male and female connectors and changes the overall dynamics of the uncoupling process. A partially separated connector assembly is an undesired condition, as it exposes the conductive projections of the male connector, creating a shock hazard. In addition, another conductive material could contact the exposed projections and cause a short circuit or fire.
Prior attempts have been made to solve this problem. For example, Schlums U.S. Pat. No. 2,051,425 teaches an electric plug having a cammed means for detaching the plug from a receptacle. The detaching means comprises a cam having an outer arm portion and an actuator portion. To uncouple the plug from the socket, the outer arm portion of the cam is depressed, causing the actuator portion to apply an oblique force against the mating surface of the receptacle, urging the plug from the receptacle due to the curvature of the actuator portion. The amount of mechanical advantage employed by the cam decreases as the outer arm portion of the cam is moved toward the plug""s housing. The stated purpose for this configuration is to match the mechanical advantage of the cam to the detaching force required, the rationale being that a greater amount of force is required to initiate separation of the plug and receptacle when the surface area contact between the male and female connectors is the greatest. The amount of force required decreases as the plug and receptacle separate.
The movement of a representative cam as disclosed by Schlums is depicted in FIG. 4. As an outer arm portion 402 of a cam 400 is pressed downward, the cam 400 rotates about a fulcrum 404. As the cam 400 rotates, an actuator portion 406 extends laterally to apply force against a mating surface 408 of a receptacle. As can be seen, the amount of lateral movement exhibited by the actuator portion 406 as the cam is rotated from position a1 to positions a2 and a3 is limited due to the curvature of the actuator portion 406, which is necessary to effect a varying mechanical advantage. Thus, to achieve the amount of cam actuator movement necessary to ensure separation of the plug and receptacle the cam as taught by Schlums would require a larger connector housing than is practical for modern power connectors.
An alternate embodiment of the electric plug as taught by Schlums features a single cam of the type generally depicted in FIG. 5 situated between the conducting projections of a male connector. The actuator portion 406xe2x80x2 of this cam 400xe2x80x2 is shaped with less curvature than the cam shown in FIG. 4 such that the actuator portion 406xe2x80x2 has little variation in mechanical advantage. In this configuration, a smaller contacting portion 510 of the actuator portion 406xe2x80x2 comes into contact with the mating surface 408xe2x80x2 of a receptacle. Although the cam 400xe2x80x2 exhibits greater lateral movement than the cam shown in FIG. 4, the amount of lateral movement is still less than necessary to ensure complete disengagement of the connector assembly.
The cams shown in FIGS. 4 and 5 both suffer from limited lateral movement of the actuator portion 406, 406xe2x80x2, which can result in incomplete disengagement of the plug and receptacle. In addition, the amount of lateral movement provided by the actuator portion 406, 406xe2x80x2 is not proportional to the movement of the outer arm 402, 402xe2x80x2. As a result, the plug begins separating from the receptacle at a slow rate as the cam 400, 400xe2x80x2 moves from position a1 to position a2, and accelerates as the connector disengagement cycle continues to position a3. The partially exposed conductive projections of the plug create a risk of arcing between conductors, short circuits, and electrical shock. Thus, it is desirable not only to ensure complete disengagement of the plug and receptacle, but also to minimize the time required to disengage the plug from the receptacle.
A further limitation of the device disclosed by Schlums is that a suitably sized actuator portion would likely interfere with a third conductor, such as the grounding terminal commonly found on modern power cords. Reducing the size of the actuator portion of the cam to eliminate such interference would only further serve to exacerbate the aforementioned limitations on lateral movement of the actuator portion of the cam, hindering full disengagement of the plug and receptacle. The grounding terminal also increases the amount of friction between the connectors. In addition, the grounding terminal extends farther than the conductive projections carrying electrical power. This is intended for safety purposes, to keep the equipment attached to the connector in a grounded state before the conductive projections carrying power are engaged and after they are disengaged. Thus, friction between mating connectors is present for a greater disengagement distance, which can cause problems for cam actuators due to their limited lateral movement and decreasing mechanical advantage during the disengagement cycle. As a result, more force must be exerted on the cam actuator to overcome the additional friction due to the grounding terminal. Moreover, the connectors may not be completely separated due to the limited lateral travel of the cam actuator.
Accordingly, a need exists to provide an electrical connector that can easily and conveniently be decoupled from its mating connector with minimal force. There is also a need for an electrical connector that can be easily separated from its mated connector when the electrical connector assembly is located in an obstructed or difficult-to-reach area. Yet another need exists to ensure rapid and complete separation of coupled electrical connector assemblies.
Preferred embodiments of the present invention satisfy the above-enumerated needs. In addition, it will be appreciated that similar advantages may be obtained in other applications of the present invention. Such advantages may become apparent from the present disclosure or through practice of the present invention.
The present invention provides an improved electrical connector as well as a method for separating coupled connectors in an electrical connector assembly. The ejectable electrical connector may be a male connector, a female connector, or any other similar, suitable, or conventional type of connector. An example of a male ejectable electrical connector is a plug, and examples of female ejectable electrical connectors include jacks, sockets, receptacles, and wall outlets. The ejectable electrical connector according to one embodiment of the invention includes a lever that is pivotally connected to the body. The lever includes an actuator portion shaped to maximize lateral movement in order to effect a substantially full detachment of the coupled connector assembly components when actuated. In addition, the lever is shaped to disengage the connectors more quickly than the prior art, thus minimizing the risk of electrical shocks, arcing, and short circuits. Gripping force may be applied to both an upper portion of the lever and the bottom surface of the connector, thereby causing the lower, opposing portion of the lever to rapidly extend from the mating surface of the ejectable electrical connector. The lever may be pivotally attached to the body of the connector in such a way as to not interfere with the connection between mating connectors during engagement. The ejectable electrical connector may be a part of an electrical connector assembly. Electrical connector assemblies may comprise a male connector, e.g., a plug, that is engaged with a female connector, e.g., a receptacle such as a wall outlet. In the present invention, the decoupling of an electrical connector assembly is accomplished by manual actuation of at least one lever that is pivotally connected to the body of at least one of the connectors.
The limitations of the prior art cam are overcome with a xe2x80x9ctype 1xe2x80x9d lever. A type 1 lever is defined by physics convention as a lever wherein the fulcrum is situated between the applied force and the load. A type 1 lever provides a constant mechanical advantage, the amount of the mechanical advantage depending on the position of the fulcrum in relation to the applied force and the load. The mechanical advantage of a type 1 lever increases as the fulcrum is moved farther away from the applied force and closer to the load. This constant mechanical advantage provides more separation force throughout the connector assembly separation process, a desirable characteristic for particularly stubborn connector assemblies or connectors having greater numbers of conductors and thus a higher friction fit.
In addition, a type 1 lever can provide greater actuator displacement than the prior art cam, ensuring complete separation of the plug and receptacle. The type 1 lever, unlike a cam, may be accommodated by the smaller housing seen in modern connectors without compromise to the lever""s travel effectiveness. A type 1 lever may also be fitted to three-conductor grounded plugs without interfering with the grounding terminal or limiting the movement of the actuator portion of the lever.
The direction of movement of the lower portion of a type 1 lever differs from the actuator portion of a cam, in that a cam exhibits a sliding action against the mating surface of the opposing connector, whereas the lower portion of a type 1 lever applies the disengaging force directly against a focused area of the mating surface of the opposing connector. This results in a faster disengagement of the connector assembly for a corresponding movement of the lever, reducing the risk of arcing, electrical shocks, and short circuits.
Although a type 1 lever is the preferred embodiment for the present invention, it should be noted that other levers, such as type 2 and type 3 levers, may also be utilized.
The present invention is not limited to any specific type or use of electrical connector. In fact, the levered ejector disclosed herein is not limited to electrical-type connectors. One preferred embodiment of the present invention is particularly useful with two-conductor or three-conductor, male or female electrical connectors, e.g., with electrical cables, extension cords, or other similar, suitable, or conventional electrical cables. Nevertheless, the present invention may be implemented with any of the connectors described above in the background as well as other similar, suitable, or conventional connectors that are now known or may be later developed. Examples of other connectors to which the present invention may be applied include, but should not be limited to, serial data connectors, parallel data connectors, and in-line connectors. The connectors may be used for any suitable purpose such as for electrical power distribution (e.g., with power strips, wall outlets, power cords, extension cords, and other similar, suitable, or conventional power distribution systems), data transmission, control signal transmission, response signal transmission, timing signal transmission, and other similar, suitable, or conventional uses that are now known or may be later developed. In addition, it should be recognized that the present invention may be used to separate connector/wall outlet assemblies as well as any other similar, suitable, or conventional type of electrical connector assembly. The present invention may also be utilized in non-electrical connectors, such as mechanical couplings in which components are coupled together through the use of friction between the mating surfaces. Such coupled mechanical connections may be purely mechanical or otherwise used to convey some medium from one connector to the other.
In addition to the novel features and advantages mentioned above, other objects and advantages of the present invention will be readily apparent from the following descriptions of the drawings and exemplary embodiments.